1 #ifndef lint
2 static char sccsid[] = "@(#)access.c 1.1 (Berkeley) 02/25/86";
3 #endif
4 /*
5 * Adb: access data in file/process address space.
6 *
7 * The routines in this file access referenced data using
8 * the maps to access files, ptrace to access subprocesses,
9 * or the system page tables when debugging the kernel,
10 * to translate virtual to physical addresses.
11 */
12
13 #include "defs.h"
14
15 MAP txtmap;
16 MAP datmap;
17 INT wtflag;
18 STRING errflg;
19 INT errno;
20
21 L_INT pid;
22
23 /*
24 * Primitives: put a value in a space, get a value from a space
25 * and get a word or byte not returning if an error occurred.
26 */
put(addr,space,value)27 put(addr, space, value)
28 off_t addr; { (void) access(WT, addr, space, value); }
29
30 u_int
get(addr,space)31 get(addr, space)
32 off_t addr; { return (access(RD, addr, space, 0)); };
33
34 u_int
chkget(addr,space)35 chkget(addr, space)
36 off_t addr; { u_int w = get(addr, space); chkerr(); return(w); }
37
38 u_int
bchkget(addr,space)39 bchkget(addr, space)
40 off_t addr; { return (byte(chkget(addr, space))); }
41
42 /*
43 * Read/write according to mode at address addr in i/d space.
44 * Value is quantity to be written, if write.
45 *
46 * This routine decides whether to get the data from the subprocess
47 * address space with ptrace, or to get it from the files being
48 * debugged.
49 *
50 * When the kernel is being debugged with the -k flag we interpret
51 * the system page tables for data space, mapping p0 and p1 addresses
52 * relative to the ``current'' process (as specified by its p_addr in
53 * <p) and mapping system space addresses through the system page tables.
54 */
access(mode,addr,space,value)55 access(mode, addr, space, value)
56 int mode, space, value;
57 off_t addr;
58 {
59 int rd = mode == RD;
60 int file, w;
61
62 if (space == NSP)
63 return(0);
64 if (pid) {
65 int pmode = (space&DSP?(rd?RDUSER:WDUSER):(rd?RIUSER:WIUSER));
66
67 w = ptrace(pmode, pid, addr, value);
68 if (errno)
69 rwerr(space);
70 return (w);
71 }
72 w = 0;
73 if (mode==WT && wtflag==0)
74 error("not in write mode");
75 if (!chkmap(&addr, space))
76 return (0);
77 file = (space&DSP) ? datmap.ufd : txtmap.ufd;
78 if (kernel && space == DSP) {
79 addr = vtophys(addr);
80 if (addr < 0)
81 return (0);
82 }
83 if (physrw(file, addr, rd ? &w : &value, rd) < 0)
84 rwerr(space);
85 return (w);
86 }
87
88 /*
89 * When looking at kernel data space through /dev/mem or
90 * with a core file, do virtual memory mapping.
91 */
vtophys(addr)92 vtophys(addr)
93 off_t addr;
94 {
95 int oldaddr = addr;
96 int v;
97 struct pte pte;
98
99 addr &= ~0xc0000000;
100 v = btop(addr);
101 switch (oldaddr&0xc0000000) {
102
103 case 0xc0000000:
104 /*
105 * In system space get system pte. If
106 * valid or reclaimable then physical address
107 * is combination of its page number and the page
108 * offset of the original address.
109 */
110 if (v >= slr)
111 goto oor;
112 addr = ((long)(sbr+v)) &~ 0xc0000000;
113 goto simple;
114
115 case 0x80000000:
116 /*
117 * In p2 spce must not be in shadow region.
118 */
119 if (v < pcb.pcb_p2lr)
120 goto oor;
121 addr = (long)(pcb.pcb_p2br+v);
122 break;
123
124 case 0x40000000:
125 /*
126 * In p1 space everything is verboten (for now).
127 */
128 goto oor;
129
130 case 0x00000000:
131 /*
132 * In p0 space must not be off end of region.
133 */
134 if (v >= pcb.pcb_p0lr)
135 goto oor;
136 addr = (long)(pcb.pcb_p0br+v);
137 break;
138 oor:
139 errflg = "address out of segment";
140 return (-1);
141 }
142 /*
143 * For p0/p1/p2 address, user-level page table should
144 * be in kernel vm. Do second-level indirect by recursing.
145 */
146 if ((addr & 0xc0000000) != 0xc0000000) {
147 errflg = "bad p0br, p1br, or p2br in pcb";
148 return (-1);
149 }
150 addr = vtophys(addr);
151 simple:
152 /*
153 * Addr is now address of the pte of the page we
154 * are interested in; get the pte and paste up the
155 * physical address.
156 */
157 if (physrw(fcor, addr, (int *)&pte, 1) < 0) {
158 errflg = "page table botch";
159 return (-1);
160 }
161 /* SHOULD CHECK NOT I/O ADDRESS; NEED CPU TYPE! */
162 if (pte.pg_v == 0 && (pte.pg_fod || pte.pg_pfnum == 0)) {
163 errflg = "page not valid/reclaimable";
164 return (-1);
165 }
166 return ((long)(ptob(pte.pg_pfnum) + (oldaddr & PGOFSET)));
167 }
168
rwerr(space)169 rwerr(space)
170 int space;
171 {
172
173 if (space & DSP)
174 errflg = "data address not found";
175 else
176 errflg = "text address not found";
177 }
178
physrw(file,addr,aw,rd)179 physrw(file, addr, aw, rd)
180 off_t addr;
181 int *aw, rd;
182 {
183
184 if (longseek(file,addr)==0 ||
185 (rd ? read(file,aw,sizeof(int)) : write(file,aw,sizeof(int))) < 1)
186 return (-1);
187 return (0);
188 }
189
chkmap(addr,space)190 chkmap(addr,space)
191 REG L_INT *addr;
192 REG INT space;
193 {
194 REG MAPPTR amap;
195
196 amap=((space&DSP?&datmap:&txtmap));
197 IF space&STAR ORF !within(*addr,amap->b1,amap->e1)
198 THEN IF within(*addr,amap->b2,amap->e2)
199 THEN *addr += (amap->f2)-(amap->b2);
200 ELSE rwerr(space); return(0);
201 FI
202 ELSE *addr += (amap->f1)-(amap->b1);
203 FI
204 return(1);
205 }
206
within(addr,lbd,ubd)207 within(addr,lbd,ubd)
208 u_int addr, lbd, ubd; { return(addr>=lbd && addr<ubd); }
209
longseek(f,a)210 longseek(f, a)
211 off_t a; { return(lseek(f, a, 0) != -1); }
212